This invention relates to polyvinyl fluoride (PVF) film and, more particularly, relates to a flame-retardant PVF film.
PVF films, and especially biaxially oriented PVF films, are well known in the art as having favorable properties of weather durability, stain resistance, and toughness. These properties have led to the use of PVF films as a protective layer in specialty applications where durability of the surface finish is an important consideration. For instance, PVF film has been used as a wrapping for electrical wire and cable and PVF film bonded to epoxy glass fiber substrate has been used as the finish surface of airplane cabin walls.
Although PVF has a low flame spread rating when compared to most synthetic resin films, such as plasticized PVC films, PVF film can be ignited and will continue to burn when the ignition source is removed. There is a continuing emphasis to improve the burn resistance of materials included in vehicle construction and thus there is a need for a more fire-retardant PVF film.
Antimony trioxide, alone or in combination with various salts, has long been proposed as a fire-retardant additive for synthetic resins such as polyvinyl chloride and polyesters. For instance, U.S. Pat. No. 3,723,139 discloses that an unfused mixture of antimony oxide and certain antimonates is useful as a fire retardant in polyvinyl chloride.